textproduct: Quad Cities

KEY MESSAGES

- A burst of accumulating dry, fluffy snow will move through the area today, mainly this afternoon and evening. A Winter Weather Advisory remains in effect, with travel impacts expected for the PM commute.

- Below normal temperatures are forecast for the entire week. Wednesday and Thursday nights look particularly cold, with around 60- 90+% chance of overnight lows below zero Thursday morning.

- Active pattern remains through the week, with periodic chances of snow mid-week and again late week.

SHORT TERM /THROUGH TONIGHT/

Issued at 309 AM CST Mon Dec 1 2025

After a cold morning for locations north of Interstate 80 (with morning lows starting off in the single digits above zero), attention quickly turns to a mid-level shortwave trough that will translate eastward today from the Four Corners region. On the northeastern flank of the shortwave, enhanced 850-700 mb layer frontogenetical forcing and increasing moisture will result in a burst of accumulating snow, mainly for this afternoon and evening. Model sounding analysis shows top-down saturation occurring as the FGEN band approaches, with an impressively deep dendritic growth zone aloft (roughly 9000 feet deep!). This is a strong indication that the snow will be of the dry, fluffy variety, with snow ratios of 16:1 to 19:1 expected. The latest HREF ensemble suggest snowfall rates most likely around 0.25 to 0.5 inches per hour, with the potential for rates to exceed a half inch per hour this afternoon. The timing of this snow will be problematic, given this will impact the PM commute today. Fortunately, the winds look to be on the weak side, so the threat for blowing and drifting snow looks quite limited. Forecast snowfall amounts appear to be on track, with most locations seeing between 1-4", with 2+" likely to be seen along and southeast of a Sigourney, IA to Mount Carroll, IL line. These are very much in line with the latest HREF probability-matched mean snowfall totals. A Winter Weather Advisory remains in effect for these locations. Make sure to take it slow on the roadways during the snow, and allow plenty of following distance if out traveling.

As we head into the overnight hours, the accumulating snow should diminish by midnight, when our advisory expires, as drier air filters in from the west. High pressure will also nose into the region, leading to a period of dry weather through Tuesday night. The main thing to watch for tonight is another night of very cold conditions, with lows expected in the single digits and lower teens.

LONG TERM /TUESDAY THROUGH SUNDAY/

Issued at 309 AM CST Mon Dec 1 2025

The main theme of the long term period will be below normal temperatures (very cold temperatures and wind chills at times), along with a few bouts of precipitation. First, let's talk temperatures. Tuesday and Wednesday high temperatures will generally be in the 20s to lower 30s, so seasonably cold for this time of the year. This is all thanks to a high pressure ridge axis that will sweep through the area, leading to southerly return flow and enhanced warm air advection.

Temperatures actually look to be their coldest of the week on Wednesday and Thursday nights as a cold front is progged to sweep through the area during the daylight hours Wednesday. Post-frontal, an arctic air mass looks to build into the region, characterized by 850 mb temperatures near -11 to -14 degrees C per the GEFS and ECMWF ensembles. This is quite cold for early December, and the ECMWF EFI shows a strong signal for consensus in the ECMWF ensembles for very cold conditions, with values of -0.8 to -0.99. In short, Wednesday night/Thursday morning is likely to be the coldest night of the season so far. NBM probabilities of low temperatures below zero Thursday morning are around 60-90+% for most locations (highest over northeastern Iowa), and even values of 20-50% for morning lows of 10 below zero or colder! Northwesterly winds post-frontal could also result in bitterly cold wind chills of less than 20 below zero, so keep an eye on the forecast as we approach Wednesday night. Thursday night could also be quite cold, although early indications suggesting not as cold as Thursday morning. Temperatures do look to moderate some next week.

Back to the precipitation potential on Wednesday with the cold front: overall, the front appears to be moisture-starved, so there doesn't appear to be much in terms of snow accumulations with it. There is a signal for a larger system to move through the area next weekend Saturday night, but there isn't as much model consensus on the timing, coverage, and intensity of the precipitation, so confidence remains low on this potential system.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 500 AM CST Mon Dec 1 2025

Mostly MVFR conditions continue to be observed over much of the area early this morning, thanks to a low stratus deck that continues to expand northward. Some IFR/LIFR conditions have been reported farther north, but confidence remains low that they will become widespread.

Attention will then turn to a quick burst of accumulating snow that will move through the area, mainly during the PM hours today. Confidence is quite high that this snow will be the dry, fluffy variety, with the latest HREF ensemble suggesting snowfall rates between 0.25 to 0.5 inches per hour, perhaps exceeding 0.5 inches per hour at times this afternoon. This should lead to IFR conditions (ceilings and visibilities), with LIFR conditions possible in the heavier snowfall (probabilities of 1/2SM visibilities between 50-70% per the HREF for BRL and MLI). Winds will generally be light and variable, so blowing snow doesn't appear to be an issue. Visibilities will improve this evening as the snow tapers off, but IFR to MVFR ceilings should continue.

DVN WATCHES/WARNINGS/ADVISORIES

IA...Winter Weather Advisory from noon today to midnight CST tonight for IAZ066>068. Winter Weather Advisory from 9 AM this morning to 9 PM CST this evening for IAZ076>078-087>089-098-099. IL...Winter Weather Advisory from noon today to midnight CST tonight for ILZ007-009-015>018-024>026-035. Winter Weather Advisory from 9 AM this morning to 9 PM CST this evening for ILZ034. MO...Winter Weather Advisory from 9 AM this morning to 9 PM CST this evening for MOZ009-010.